Most IC devices are assembled around a lead frame. These lead frames are commonly of various sizes dependent upon the size of the chip, e.g., the semiconductor chip, and the number of connections that are made to the chip. Such lead frames are usually manufactured in long strips of many individual units. The long strips often are wide enough to accommodate from one to more than five lead frames. When a lead frame strip is more than one lead frame wide, the strip is referred to as a matrix.
The evolution of IC devices generally has been toward smaller circuitry with greater packaging density. Packaging density refers to "high pin count" or "fine pitch" lead frames which have a large number of leads and currently are used in the most powerful IC devices. The desirability of such lead frames may be offset to some extent by the high tooling costs in creating stamped lead frames or establishing lead frame etching processes and the uncertain product life of new lead frame configurations.
Lead frames for a given IC device have their own shape, i.e., their own width and length, dependent upon the size of the chip. Particularly, the size of the chip dictates the size of the die or chip pad, which is an area of the lead frame upon which the chip is mounted. Further, the leads are spaced around and connected to the chip. Thus, adequate lead size and spacing is maintained, such that the leads may receive wire bonds connecting the leads to the chip's bond pads.
Because of the many sizes of die pads upon which a chip may be mounted, there are currently many different sizes and configurations of lead frames, such as quad or dual-in-line configurations. Each of these lead frames is manufactured separately by lead frame suppliers and IC device manufacturers. Complicated lead frame configurations may be made by expensive stamping tools and dies. Further, preparation of stamping equipment or etching processes for manufacturing such lead frames may result in increased lead frame costs and extended cycle time from demand through development to production. These costs and delays may be reincurred with each new lead frame design.